A modular tray is described for use as an element for constructing a green roof and, more particularly, a modular tray for use in pitched green roof.
A green roof is a roof or other structure at least partially covered by vegetation, providing numerous benefits to the building. For example, a green roof system significantly reduces storm-water runoff and filters the water that does run off of the roof.
Modular green roof systems utilize portable trays that function as independent growing containers. The modular trays make green roof design and construction more widely accessible. The trays may be delivered to the site as fully grown units that are simply laid in place on the roof. The trays are typically plastic trays with drain holes provided along the sides or the bottom. The trays are filled with growing medium and plants and placed on a roof. Excess rainwater is intended to flow through the tray out of the holes and onto the roof.
Most modular green roof trays are designed for flat or low-slope roofs. One concern of pitched roofs is an unequal water distribution from top to bottom of the roof simply due to gravitational effects resulting in drier conditions at the top and wetter conditions at the bottom of an inclined or pitched roof. Modular trays designed to retain specific amounts of water on flat roofs, and thus be self-sustaining, cannot retain this water on pitched roofs. Therefore, the modular trays do not perform as well on pitched roofs or require irrigation systems to make up for the lack of collected water in the module. Sloped roof applications often require considerable improvisation and custom engineering.
For the foregoing reasons, there is a need for a modular tray for use in a green roof system on a sloped roof. The new modular tray should be easily transported and reliably installed and provide for moisture collection and retention in the modular tray in the sloped roof application.